Elliot Rodger stood in the doorway , talking to sheriff 's deputies who had come to check on his welfare , and worried that his plan to kill was over .

Last month , officers visited Rodger , 22 , who they say killed six people and himself Friday night , at his apartment in Isla Vista , California .

`` I had the striking and devastating fear that someone had somehow discovered what I was planning to do , and reported me for it , '' Rodger wrote toward the end of a 137-page account of his life . `` If that was the case , the police would have searched my room , found all of my guns and weapons , along with my writings about what I plan to do with them .

`` I would have been thrown in jail , denied of the chance to exact revenge on my enemies . I ca n't imagine a hell darker than that . ''

The manifesto , titled `` My Twisted World , '' was obtained by CNN affiliate KEYT .

`` It was apparent he was very mentally disturbed , '' Santa Barbara County Sheriff Bill Brown said , referring to the contents of the autobiography .

So disturbed that someone from a mental health agency , after consulting with one of Rodger 's relatives , requested police check on his welfare April 30 , Brown said .

Rodger 's family contacted police after discovering social media posts about suicide and killing people , family spokesman and attorney Alan Shifman told reporters Saturday .

Brown said Rodger told deputies it was a misunderstanding and that he was not going to hurt anyone or himself . Rodger said he was having troubles with his social life .

`` He was articulate . He was polite . He was timid , '' Brown told CNN on Sunday .

There was nothing in his behavior to suggest he was violent , and the deputies `` determined he did not meet the criteria for an involuntary hold , '' Brown said .

Rodger wrote that a wave of relief came over him when the deputies left . `` If they had demanded to search my room ... -LRB- t -RRB- hat would have ended everything . For a few horrible seconds , I thought it was all over . ''

After that , Rodger wrote , he kept one of his guns and some loaded magazines near him so if police came back to his apartment , he would try to shoot them and escape . `` Thankfully , all suspicion of me was dropped after I took down the videos from Youtube , and the police never came back . ''

`` It was all because of the videos . I must have expressed too much anger in them . I immediately took most of them off of Youtube , and planned to reupload them a few days before the Day of Retribution . '' Rodger uploaded a video Friday , calling it his last .

Sheriff : Plan took a year

The angst leading up to Friday 's evening of horror was years in the making . The plan to kill many people apparently had come together in the past year , Brown said .

Rodger was frustrated by his short stature , his parents ' divorce and his lack of success with women -- and chronicled his perceived misfortunes in his manifesto .

He picked Friday to launch a killing rampage , outlined later by police .

It started at his own home in Isla Vista , near the scenic beaches of Southern California . Rodger stabbed three men to death at his home . They are Cheng Yuan Hong , 20 , and George Chen , 19 , both of San Jose , and Weihan Wang , 20 , of Fremont , the Santa Barbara County Sheriff 's Office confirmed Sunday .

They were students at the University of California , Santa Barbara , the Sheriff 's Office said . Hong and Chen were `` listed on the lease for the apartment as tenants , along with Rodger , '' the Sheriff 's Office said .

Rodger then took his handguns and went to the Alpha Phi sorority house near UC Santa Barbara campus ; he hinted at the carnage he 'd inflict at the sorority house in the YouTube video called `` Retribution . ''

`` On the day of retribution I 'm going to enter the hottest sorority house of UCSB , '' he said in the video . `` I 'll take great pleasure in slaughtering all of you . ''

On Friday night , sorority members heard loud knocking on the front door for several minutes -- but nobody answered .

Minutes later , Rodger sprayed bullets at the house from across the street , Brown said .

Witness Kyle Sullivan saw three young women lying on the front lawn .

`` There was a young girl , laying right here . And she was -- I could tell immediately she was gone , '' said Sullivan , 19 . `` I saw a gunshot wound to her abdomen , also one to her side and one through her head . ''

She was n't alone .

`` There was a girl right here and she was really struggling . You could tell she was barely able to move her eyes and just moving her arms slightly , '' Sullivan said . `` And there was another girl right here . You could tell she was lying down crouched . She was still conscious , talking . ''

By the end of the night , two of the three young women had died -- Katherine Cooper , 22 , and Veronika Weiss , 19 . Both were students at UC Santa Barbara .

Delta Delta Delta said on its Twitter page Sunday that it mourned the loss of two of its sisters .

`` Tri Delta is saddened by the tragic loss of two members at UCSB . Our thoughts are with their family , friends , and Gamma Theta Chapter , '' the message said .

Alpha Phi posted on its Facebook page Saturday that `` all our members are safe . ''

Rampage continues

Rodger then zoomed around town in a black BMW , stopping at a delicatessen where he shot and killed Christopher Martinez , another UC Santa Barbara student .

Exactly why , no one knows for sure .

Rodger got back in his car , and the killing rampage continued .

He dashed around town , reportedly driving down the wrong side of the road so he could fire out the driver 's side window near the sidewalk . He shot at two people on the sidewalk , pulled a handgun on a woman and fired some more , Brown said .

He encountered a sheriff 's deputy who was on foot and exchanged gunfire .

Witness Ian Papa said he was inches away on the street when the gunman 's car sped up and struck two bicyclists .

`` It happened so fast , '' he said . `` I had no time to react . I jumped on the sidewalk and I see a man on a BMW , his body inside the windshield and glass broken everywhere . ... I almost wanted to break into tears . ''

The nightmare finally ended after Rodger slammed into a parked vehicle and apparently shot himself in the head , police said .

By the time the melee was over , six victims were dead , 13 were injured , and a quiet beachfront community was left to wonder how this could happen -- and whether anyone could have prevented it .

In the nearly seven-minute video posted Friday , Rodger rants about women who ignored or rejected him over the past eight years , `` since I hit puberty . ''

`` Tomorrow is the day of retribution , the day in which I will have my revenge , '' he says in what he calls his last video . `` You girls have never been attracted to me . I do n't know why you girls are n't attracted to me , but I will punish you all for it . '' He specifically criticized sorority members .

Unused ammo

It 's unclear what Rodger might have done had he not wrecked his car . Inside the wrecked BMW , Brown said , police found three handguns -- all legally purchased -- and more than 400 rounds of unused ammunition . Brown said the guns were purchased the firearms over the past year in three different cities .

Martinez 's father , Richard , said some politicians and the National Rifle Association are also to blame for his son 's death .

`` Chris died because of craven , irresponsible politicians and the NRA , '' he said . `` They talk about gun rights -- what about Chris ' right to live ? When will this insanity stop ? ''

Rodger suffered from an undisclosed mental health issue and was under the care of a variety of health care professionals , Brown said .

But there was no indication he had been committed to a mental health facility .

Rodger passed the background check needed to buy the firearm used in the shooting , a law enforcement official briefed on the investigation told CNN . The official said nothing had been found in the gun trace to indicate Rodger should have been disqualified .

Law enforcement officers were searching the separate homes of the suspect 's mother and father Sunday , a law enforcement official with knowledge of the investigation told CNN . The officers were from the Santa Barbara County Sheriff 's Department and the U.S. Bureau of Alcohol , Tobacco , Firearms and Explosives , the source said .

The manifesto

In the manuscript of his life 's story , Rodger often mentioned feeling slighted or inferior , such as when he was denied entry on an amusement park ride at age 6 while other boys his age got to go on .

`` Being denied entry on a simple amusement park ride due to my height may seem like only a small injustice , but it was big for me at time , '' Rodger wrote . `` Little did I know , this injustice was very small indeed compared to all the things I 'll be denied in the future because of my height . ''

He described his parents ' divorce as a devastating , `` life-changing event , '' but said he gained more respect for his father after he quickly acquired a girlfriend .

`` Males who can easily find female mates garner more respect from their fellow men , even children , '' Rodger wrote . `` How ironic is it that my father , one of those men who could easily find a girlfriend , has a son who would struggle all his life to find a girlfriend . ''

But the overarching theme of the manifesto focuses on his frustrations with women .

`` My orchestration of the Day of Retribution is my attempt to do everything , in my power , to destroy everything I can not have , '' Rodger wrote .

`` All of those beautiful girls I 've desired so much in my life , but can never have because they despise and loathe me , I will destroy . All of those popular people who live hedonistic lives of pleasure , I will destroy , because they never accepted me as one of them . I will kill them all and make them suffer , just as they have made me suffer . It is only fair . ''

Who 's the man behind the rampage

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Names of three other victims released

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Elliot Rodger had guns and plans to kill people when deputies came to his home

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Authorities say he killed 6 people Friday before apparently shooting himself in the head

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Rodger wrote 140 pages about his life and frustrations about women